Waste Disposal

ABSTRACT

A gaseous-liquid mixture for use with a pressurized spray container, said mixture being capable of forming solid foam of polymer in open air, wherein said mixture comprises a polymer, a highly volatile non-poisonous organic solvent, and a propellant gas, said mixture being prepared from powder of said polymer dissolved in said solvent, such that said foam solidifies in open air in about one minute or less.

FIELD OF THE INVENTION

This invention relates to a device and method of disposal of solidwaste, in particular pet excrements.

BACKGROUND OF THE INVENTION

Dogs are so important for human society. There is no doubt that dogs arethe most important pets grown by people. Having dogs in private homes inmodern, westernized society raises a serious problem: dogs have to betaken outside the homes several times a day for trips in the streets, inorder to allow them to excrete and breath fresh air. Hygiene regulationsin most of modern cities do not allow the owners of dogs to leave dogsexcrements on the streets and even on park alleys and lawns. People whowalk their dogs have to carry with them tools for collecting the dogexcrements and put them in the garbage cans (e.g. the so called ‘pooperscooper’ in the US). Carrying such tools whenever taking a dog to a tripoutside, makes such trip unpleasant and uncomfortable.

One would suggest dogs owners to carry with them plastic bags in whichthey should put their dog litter when it lays on the street. However thetouch of the hand to the warm, humid dogs excrements even through aplastic bag is also very unpleasant and disgusting. U.S. Pat. No.4,900,077 and U.S. Pat. No. 5,540,470 suggest portable mechanicaldevices which facilitate the scooping of litter, without touching it,into a disposable plastic bag. U.S. Pat. No. 4,718,707 discloses anentirely disposable waste scooper comprising a U-shaped wire frame, aplastic bag and a cardboard lid. These devices facilitate the scoopingand disposal procedure but do not remove the unpleasant sensation.

DE3333887 describes a spray container for excrement disposal containingquick hardening polymer composition. The sprayed composition forms alayer of cellular foam over the faeces such that it can be taken by handand stored in a plastic bag provided with the same container. The patentapplication does not define specific components of the foam composition.The inventor states that the foam should harden in seconds and suggestsemploying well-known polyurethane and epoxy resin sprays used inindustry for mounting window frames and the like. However, thesepolymers are formed in situ, by polymerization chemical reaction, whichis known to take several minutes, even tens of minutes.

DE19937983 describes foam for excrement disposal which creates stableisolation layer after the application and makes the faecesunrecognizable. The foam is applied from a spray container and becomeshard in less than 3 hours, preferably in 5 minutes. It is suggested thatthe excrement can be simply allowed to remain on the street, since theisolating layer remains stable even if a person steps in the excrement.The foam-forming fluid contains gelatin dissolved in alcohol and thepropellant gas is CO₂ or air.

Hence, it is clear that so many dog owners are waiting and seeking anelegant solution to the problem described above, namely, how to get ridof dog excrements in an easy way, without carrying collection tools,plastic bags etc, and yet leaving the streets clean as demanded by theauthorities.

Similar and even more basic problems arise with other kinds of solidwaste, which may be not only unpleasant but mechanically, biologicallyor chemically hazardous, when such waste is spilled in unprepared placeor in unexpected way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a spraycontainer for disposal of solid waste, filled with pressurizedgaseous-liquid mixture capable of forming solid foam in open air. Themixture comprises a polymer, a highly-volatile non-poisonous organicsolvent, and pressurized gas. The solid foam has good adhesion to thewaste and weak adhesion to hard solid surfaces and skin. The foamsolidifies in the open air in about one minute or less. Preferably, thefoam is formed with closed bubbles.

In one embodiment of the present invention, the spray container is ofpocket-size and is adapted to deliver multiple portions of foam. Thefoam solidifies in open air in about half a minute or less, whereby itis suitable for disposal of such solid waste as pet's excrements.Preferably, the container is adapted for being carried attached to aperson's body or clothing, or to pet's walking accessories. For thispurpose, the spray container may comprise means for attaching to belts,textile fabric (clothes), pet leash, pet collar, or pet leash reel.

The spray container is preferably adapted to meter out portions of foamof limited predetermined quantity, and preferably this predeterminedquantity is adjustable within a predetermined range.

In accordance with another aspect of the present invention, there isprovided gaseous-liquid mixture for use with the above spray container,for disposal of solid waste. The polymer in the mixture may be one ormore of the group: polystyrene, PVC, rubber, polyethylene glycol nylons,polyesters, polycarbonate, and polyacrylate. The organic solvent may beone or more of the group: diethyl ether, ethyl acetate, ethanol,methylene chloride, acetone, freon, and three chloro ethane. Thepressurized gas may be one or more of the group: carbon dioxide, butane,and propane.

The gaseous-liquid mixture may be made up of PVC, methylene chloride andpropane or carbon dioxide, for example in proportion 80 g of PVC,approximately 300 g of methylene chloride and 2 g of the pressurizedgas.

The gaseous-liquid mixture may be also prepared on the basis ofpolystyrene, acetone and carbon dioxide.

Preferably, the gaseous-liquid mixture contains two polymers from thegroup: polystyrene, PVC, rubber, polyethylene glycol nylons, polyesters,polycarbonate, and polyacrylate, while the organic solvent is a mixtureof at least two solvents, one polar solvent such as ethyl acetate,ethanol, or three chloro ethane, and one less polar solvent such asdiethyl ether, or methylene chloride.

The solidifying foam may contain antiseptic or germicide or deodorantadditives; and/or it may contain surfactant additives to enhance formingof closed bubbles.

In the specific embodiment for disposal of pet's excrements, thesolidifying foam may further contain a substance-indicator of apredetermined chemical property or component of the pet's excrements,thereby allowing diagnostics of a medical condition.

In accordance with yet another aspect of the present invention there isprovided a method for disposal of hazardous and/or unpleasant solidwaste in a waste-disposal container, the method comprising:

-   -   providing a spray container loaded with pressurized        gaseous-liquid mixture capable of forming solid foam in open        air, the solid foam having good adhesion to the solid waste and        weak adhesion to hard solid surfaces and skin;    -   spraying a portion of the foam over the solid waste so that the        solid waste is covered from all sides and forms an integral body        with the foam;    -   waiting a period of time necessary for the foam to solidify; and    -   taking the integral body by fingers, touching only the foam        portion, and placing it in said waste-disposal container.

The present invention is an elegant solution to the problem of disposalof specific kinds of solid waste. In particular, using appropriatecombinations of organic solvents, gases and polymeric species, it ispossible to form mixtures that can be stored in small aerosolcontainers, thereby solving the problem of dog's excrements. When suchmixture is sprayed out of the container on a dirty object, it forms asolid crust in a very short time. Then, the dirt can be immediatelyremoved and be thrown to the closest garbage can, so that the user hasno direct touch with it and has no need to watch over the excrement foran inconveniently long period of time.

The solidifying foam may contain surfactant additives to enhance formingof closed bubbles. Such foam is a better insulator than material withcommunicating pores, does not absorb humidity and provides for moreeconomical usage of the materials.

It is possible to select materials that are cheap and environmentallyfriendly (e.g. most of commonly used thermoplastic polymers, alcoholsand carbon dioxide). Hence, such a product can be distributed by anysupermarket, shops for food, general supplies, pharmacies etc.

The above method of waste disposal may be implemented in such facilitiesas operation rooms, biological and chemical laboratories where the solidwaste may be not only unpleasant but mechanically, biologically orchemically hazardous, and may be spilled in unprepared place or inunexpected way as a result of breaking flasks, tubes, etc.

The speed of foam hardening is achieved by using very volatile solventsand ready polymers that are dissolved in the solvent. The setting(hardening) is faster at higher ambient temperature. The inventors havetested specific gaseous-liquid mixtures where the polymer is a mixtureof polystyrene and poly-methyl- metacrylate, the solvent is methylenechloride or diethyl ether. The propellant gas may be carbon dioxide, LPGor propane.

For the preparation of the mixture, polymer powder is dissolved in thevolatile solvent at room temperature. Then aerosol (spray) containersare filled with the solution and pressurized by pumping in thepropellant gas to about 6 ata.

The mixture of polystyrene and poly-methyl-metacrylate may be in weightratio from 1:3 to 3:1, preferably 1:1. The mixture may contain, per 1liter of the solvent, from 50 to 500 g of each of the polymers and 2 to4 g of CO₂. Preferably, it may contain, per 1 liter of said solvent, 150g of each polymer and 3 g of CO₂.

The mixtures are hardening in less than a minute at body temperature andin less than two minutes in the range 10-20° C. Such mixtures can beused in other areas besides disposing of waste. For example, coating ofmetal structures to prevent corrosion, electric insulation coatings,sealing of pipes and containers to prevent penetration (leakage) of gas,oils, water, chemicals or dust, electric conductor coatings to preventelectric shocks, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, a preferred embodiment will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 shows a dog on a leash, equipped with a spray container of thepresent invention;

FIG. 2 shows the usage of the spray container for forming a solid foambody over dog's excrements.

FIG. 3 shows the disposal of the solid foam body by hand.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, there is shown an example of spraycontainer 10 for disposal of pet's excrements, loaded with pressurizedgaseous-liquid mixture that forms solid foam in open air. The spraycontainer 10 is of pocket size and is attachable to a leash 12 of a petdog 14. The spray container can deliver multiple portions of foam. Thecontainer has a spray valve 16 which may be adapted to dispense portionsof foam of predetermined quantity and this quantity may be manuallyadjustable.

The process of disposal by means of the foam in the spray container 10is shown in FIGS. 1, 2 and 3. After the dog 14 delivers excrements 18,the dog owner takes the spray container 10 from the leash 12 and sprayspulverized foam 20 over the excrements 18 covering them from all sides.The foam then sets to form a solid body 22 with the excrements 18embedded therein. The solid body 22 however has clean upper surface, sothat the dog owner easily takes it by his fingers and throws it into anearby litter bin 24.

It would be appreciated that the foam must have some specific propertiesin order to serve its purpose. The solid foam should have good adhesionto the solid waste (excrements) but should not stick tight to hard solidsurfaces such as asphalt, concrete, bricks, ceramic tiles, etc.Actually, what is needed is solidifying foam detachable from the solidsurface by a slight side pressure which would not crush the foam itself.The foam should not stick also to the fingers (skin). The time of foamsetting (solidifying) should be short enough, not to extendsignificantly the waiting period for the dog owner and to cause perhapsembarrassment. A suitable setting time would be about half a minute,preferably about 10-15 sec.

Antiseptic or germicide or deodorant additives may be used. Thesolidifying foam may further contain a substance-indicator of apredetermined chemical property or component of the pet's excrements,thereby allowing diagnostics of a medical condition. Additionally,surface active substances may be added in order to enhance formation ofclosed bubbles in the foam.

The mixture for the solidifying foam meeting the above requirements isprepared on the basis of materials that are cheap and environmentallyfriendly (e.g. most of commonly used thermoplastic polymers, dissolvedin non-toxic solvent with added non-toxic aerosol-forming gas). Forexample, polymers may be polystyrene, PVC, polyacrylate, rubber,polyethylene glycol nylons, polyesters, or polycarbonate. The non-toxicsolvent may be freon, ethers, methylene chloride, acetone,three-chloro-ethane, or a low paraffin. The aerosol-forming gas may becarbon dioxide, butane, and propane. Combinations of the above materialsmay be used, for example a mixture of polystyrene, acetone and carbondioxide.

Good results, for example, were obtained by using a mixture of 80 g PVC(the polymer), 300 g methylene chloride (the solvent), and 2 g CO₂ orpropane (the gas). The preparation consisted in dissolving PVC powder inmethylene chloride by simple mixing. The container was filled with thesolution and then filled with gas under 2 to 6 ata pressure. Whensprayed in the open air, the mixture formed very quickly a flexible PVCmatrix, as the solvent is very volatile. In less than a minute, drylayer of polymer foam with closed bubbles was formed.

The mixture can be further optimized, for example, for obtaining fastersetting time, by using multi-component mixtures. We have found that itmay be advantageous to use two or more polymers from the above list.Also, it will be advantageous to use a mixture of solvents including atleast one polar solvent (such as ethanol, ethyl acetate, ortri-chloro-ethane) and one less polar solvent (such as diethyl ether ormethylene chloride).

It would be appreciated, that other suitable properties of the foam maybe obtained, for example the solid foam may be degradable in the longterm by such factors as oxygen, humidity, solar radiation, temperature,biological factors, etc.

The above-described approach may be applied to other kinds of solidwaste. A method for disposal of hazardous and/or unpleasant solid wastein a waste-disposal container, would then comprise:

-   -   providing a spray container loaded with pressurized        gaseous-liquid mixture capable of forming solid foam in open        air, the solid foam having good adhesion to the solid waste and        weak adhesion to hard solid surfaces and skin;    -   spraying a portion of the foam over the solid waste so that the        solid waste is covered from all sides and forms an integral body        with the foam;    -   waiting a period of time necessary for the foam to solidify; and    -   taking the integral body by fingers/hands, touching only the        foam portion, and placing it in said waste-disposal container.

Understandably, in some of the applications, the foam setting time maybe longer than indicated above, or the spray containers may be largerthan pocket-size.

The present invention is an effective solution to the problem ofdisposal of specific kinds of solid waste, which may be not onlyunpleasant but also mechanically, biologically or chemically hazardous.It is especially useful when such waste is spilled in an unpreparedplace or in unexpected way, i.e. breaking a container in a laboratory oroperation room.

The inventor has found a particularly preferable example of the abovegaseous-liquid mixture where the polymer is a mixture of polystyrene andpoly-methyl-metacrylate, the solvent is methylene chloride or diethylether.

An exemplary receipt for preparing the mixture would be as follows. Take1 liter methylene chloride at room temperature. Dissolve in this solvent150 g of polymethyl metacrylate and 150 g of polystyrene (powders) bystirring (2 hours). Fill aerosol containers of 0.5 l with 250 cc ofsolution. Add 3 g of CO₂ to form a pressure of about 6 ata.

The range of the weight of the two polymers for 1 liter solvent can varyfrom 50 to 500 g and the ratio between the polymers can vary between 1:3to 3:1. The methylene chloride solvent can be replaced by diethyl ether.The amount of the gas can vary from 2 to 4 g. It is possible to usepropane or LPG instead of CO₂, in which case the quantity of thepropellant gas is somewhat larger, 50-70 g.

The quickly hardening foam of the present invention may be used in manyfields where fast hardening is necessary, for example:

-   -   coating of metal structures to prevent corrosion;    -   electric insulation coatings;    -   sealing of pipes and containers to prevent penetration (leakage)        of gas, oils, water, chemicals or dust;    -   electric conductor coatings to prevent electric shocks.

For each specific purpose, suitable additives may be used.

1. A gaseous-liquid mixture for use with a pressurized spray container, said mixture being capable of forming solid foam of polymer in open air, wherein said mixture comprises a polymer, a highly volatile non-poisonous organic solvent, and a propellant gas, said mixture being prepared from powder of said polymer dissolved in said solvent, such that said foam solidifies in open air in about one minute or less.
 2. A gaseous-liquid mixture for use with a pressurized spray container, said mixture being capable of forming solid foam of polymer in open air, said mixture comprising said polymer dissolved in a highly volatile non-poisonous organic solvent, and a propellant gas, such that said foam solidifies in open air in about one minute or less, wherein said polymer is polystyrene or poly-methyl-metacrylate, or a mixture of both; and said solvent is methylene chloride or diethyl ether.
 3. The gaseous-liquid mixture of claim 2, wherein said propellant gas is CO₂, LPG or propane.
 4. The gaseous-liquid mixture of claim 2, wherein said polymer is a mixture of polystyrene and poly-methyl-metacrylate, in weight ratio from 1:3 to 3:1.
 5. The gaseous-liquid mixture of claim 4, wherein said mixture contains, per 1 liter of said solvent, from 50 to 500 g of each of the polymers and 2 to 4 g of CO₂.
 6. The gaseous-liquid mixture of claim 4, wherein said mixture contains, per 1 liter of said solvent, from 50 to 500 g of each of the polymers and 50 to 70 g of LPG or propane.
 7. The gaseous-liquid mixture of claim 4, wherein said polymer is a mixture of polystyrene and poly-methyl-metacrylate, in equal weight ratio.
 8. A spray container for disposal of solid waste containing pressurized gaseous-liquid mixture according to claim
 2. 9. The spray container of claim 8, wherein said container is pocket-size, said solid waste is pet's excrements, and said foam solidifies in open air in about half a minute or less.
 10. The spray container of claim 9, wherein said mixture is pressurized at 2 to 6 ata.
 11. The spray container of claim 9, wherein said foam is formed with closed bubbles.
 12. A method for disposal of solid waste in a waste-disposal container, the method comprising providing a spray container loaded with pressurized gaseous-liquid mixture according to claim 2, said mixture being capable of forming solid foam of polymer in open air, said solid foam having good adhesion to said waste and weak adhesion to hard solid surfaces and skin; spraying a portion of said foam over said solid waste so that said waste is covered from all sides thereof and forms an integral body with the portion of foam; waiting a period of time necessary for the foam to solidify; and taking said integral body and placing it in said waste-disposal container.
 13. A gaseous-liquid mixture according claim 2 for disposal of solid waste.
 14. A gaseous-liquid mixture according to claim 13, wherein said waste is pet's excrements.
 15. The gaseous-liquid mixture of claim 14, further containing a substance-indicator of a predetermined property or component of pet's excrements, thereby allowing diagnostics of a medical condition of said pet.
 16. The gaseous-liquid mixture of claim 14, further containing an antiseptic or germicide or deodorant substance.
 17. The gaseous-liquid mixture of claim 14, further containing a surfactant additive.
 18. The gaseous-liquid mixture of claim 14, wherein said solid foam is degradable. 